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Yr 2 - IBMS > Carbohydrates and Diabetes > Flashcards

Carbohydrates and Diabetes Flashcards

1
Q

Define Monosaccharide, giving 3 examples and where they are found.

A

Simple sugar.

Glucose - fruit, veg, honey
Fructose - fruits, manufactured food
Galatactose - digestion of lactose

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2
Q

Define Disaccharide, giving 3 Examples and where they are found.

A

2 simple sugars linked by glycosidic bond between anomeric hydroxyl of cyclic sugar and hydroxyl of second sugar.

Maltose - malt wheat, barley, beer
Sucrose - most common - table sugar, sugar cane, sweet root veg
Lactose - milk

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3
Q

Define Oligosaccharide.

A

Chain of 3+ monosaccharides linked by glycosidic bonds

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4
Q

Define Polysaccharide and state the predominant mono. and provide other examples

A

Multiple sugars linked by glycosidic bonds.

D-Glucose

starch, glycogen and cellulose

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5
Q

Starch is a Polysaccharide. State where it is Found and the Two Types of Starch.

A

Plant cells

unbranched = amylose α-1,6-D
branches = amylopectin α-1-4-D

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6
Q

Glycogen is a Polysaccharide. State where it is Found and Explain the Features of its Structure.

A

found as a stored carbohydrate in animals

Highly Branched
- surface area for breakdown
Compact from polymer chain coiling
- allows large amount of energy storage

Glycosidic bonds between single chains = a-1,4 link

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7
Q

Where are Carbohydrates Generally Found?

A

in breads, milk, bean, corn

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8
Q

How are Carbohydrates Formed? (think organically)

A

Photosynthesis

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9
Q

Provide the 2 Types of Photosynthesis.

A

Light Dependent
light energy+water ➵ oxygen+ATP+NADPH

Light Independent - Calvin cyle
CO2+ATP+NADPH➵glucose+ADP+Pi+H20+NAP

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10
Q

What are the Functions of Carbs? (5)

A
  • energy storage
  • energy production
  • build macromolecules - DNA, ATP
  • assist in lipid metabolism
  • biosynthesis of amino acids
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11
Q

How is Starch Released, and in which pH?

A

By serous acini in pH 6.7

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12
Q

Give 3 Enzymes used to break down the Main 3 Disaccharides.

A

Maltase
Sucrase
Lactase

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13
Q

How is more Glucose made, if not from Food?

A

gluconeogenesis

  • glycerol is broken down into glucose
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14
Q

What are the Daily Requirements for Carbs?

A

2-5 = 15grams
5-11 = 20grams
11-16= 25grams
16-18 = 30grams

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15
Q

Why Can’t Cellulose be Digested?

A

enzymes can’t hydrolyse the β-1 bonds

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16
Q

3 Places Where Carbohydrates are Digested.

A

in the oral cavity
in the stomach
in the gastro-intestinal tract of the small intestine

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17
Q

Explain the Two Types of Digestion in the Oral Cavity and the end result?

A

Mechanical - by parotid and submandibular gland

Chemical - enzymatic
- salivary α-amylase

end result = broken down into monosaccharides

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18
Q

Explain How Salivary α-Amylase is Secreted in the Oral Cavity, the pH it Works at and the Function.

A
  • by serous acini of parotid and submandibular gland
  • optimum pH = 6.7
  • it hydrolyses α-1,4-linkage from oligo into poly
  • works for 1-2 hrs in the stomach before deactivation by gastric acids
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19
Q

State the 2 Enzymes found in the GIT.

A
  • pancreatic amylase
  • brush border enzymes
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20
Q

What is Pancreatic Amylase Secreted by? Where is it Secreted? What is the Optimum pH and Function?

A
  • secreted by pancreatic exocrine acini into duodenum through pancreatic duct
  • pH = 6.7-7
  • hydrolyse α-1,4-linkage and digests more complex carbohydrates
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21
Q

What is the Function of Microvilli in the Small Intestine?

A

to increase SA, facilitating absorption

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22
Q

How is Galactose and Glucose Absorbed? (4)

for jokes rememberance: The G is SOOO big how can it get through, there

A
  • from intestinal lumen, enters epithelial cell via apical border
  • uses active transport and sodium dependent co-transporters (SGLT1)
  • leaves epithelial cell via basolateral side
  • facilitated diffusion and glucose-cotransporter 2 (GLUT2)

= into blood circulation

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23
Q

How is Fructose Absorbed?

For jokes: F looks like a 5

A
  • from intestinal lumen, enters epithelial cell with GLUT-5
  • binds and changes shape
  • Leave cell - facilitated diffusion and GLUT-2

= into blood circulation

24
Q

What Problems are there With Monosaccharides being Absorbed?

A

the shape makes them polar
= unable to cross the liquid bilayer

solution - need transporter enzymes

25
Q

What Factors Affect the Rate of Monosaccharide Absorption?

A

slowed down if:
- mucosa has inflammation or injury

increased if:
- thyroid hormones are active
- mineralocortoids present e.g. aldosterone
- higher sodium concentration - Na/K pump

26
Q

What is Glucagon, Where is it Made, Where it is Stored and its Function.

A

Hormone secreted by the α cells in the Islets of Langerhans in the pancreas

stored in the muscles and liver

function = glycogenolysis
- to convert glycogen into glucose.
- adrenaline also promotes breakdown

27
Q

What is Glycogenolysis?

A

the breakdown of stored glycogen in the liver into glucose by glucagon to release into the blood stream when blood glucose is low

28
Q

What is Insulin, Where is it Made, How is it Made (7) and the Function.

A

A hormone secreted by the β cells in the Islets of Langerhans in the pancreas

How?
- translated by RNA - propreinsulin
- formed in the RER
- packaged into proinsulin - 3 peptide chains
= A chain, B chain and C chain
- proinsulin moves to transgolgi apparatus
- loses C chain, released into blood
- A and B join by disulphide bond
- insulin exits via exocytosis

function = glycogenesis
- glucose into glycogen

29
Q

What is Glycogenesis?

A

the stimulation of GLUT 4 to uptake glucose into glycogen by insulin when blood sugar levels are high

30
Q

What is Insulin Resistance?

A

When receptors aren’t receptive to insulin present in the body

31
Q

What is GLUT 4 and its Relevance to Diabetes.

A

an insulin regulated transporter responsible for glucose uptake

  • forms hypoglycaemic drugs in Diabetes Type II
  • phosphorylate GLUT4 to make it more available and lowering sensitivity to insulin
32
Q

What Happens when there is a Deficiency of Insulin?

A

leads to extracellular hyperglycaemia, intracellular hypoglycaemia and diabetes mellitus

33
Q

What are the Normal BG Levels?

A

Fasting = 80-90mg/100ml
After a Meal = 120-140mg/100ml

34
Q

What is Diabetes Type I and Type II?

A

Type I = insulin deficiency
- the pancreas doesn’t make insulin as the immune system attacks the Islet cells

Type II = insulin resistance
- pancreas produces more insulin to uptake blood sugar but overtime cells stop responding to insulin, pancreas stops making insulin

35
Q

State Symptoms of Diabetes (8) PKFVWWXY

A
  • pee more with more glucose in the urine
  • higher loss of ketones - fat breakdown
  • fatigue
  • blurred vision
  • impaired wound healing
  • unusual weight loss or gain
  • dry mouth - cells are dehydrated due to hyperosmotic plasma, can lead to hyperglycaemic coma
  • yeast infections

if something hyper - its high, so where must it all be? not in the cell

36
Q

What are the Macrovascular Complications of Diabetes?

A

large vessels that are damaged by hyperglycaemia

brain - cerebrovascular diseases, stroke, transient ischaemia, cognitive impairment
heart - corny syndrome, heart attack, congestive heart failure
extremities - diabetic foot, skin ulcer, amputation

37
Q

What are Microvascular Complications of Diabetes? eye, kidney, nerves

A

Eye - retinopathy, cataracts, glaucoma
Kidney - nephropathy, microalbuminuria, renal failure
Nerves - neuropathy

38
Q

Relevance of Diabetes to Dentistry (5)

A
  • dry mouth - caries, no saliva
  • gum and periodontal disease
  • loss of teeth
  • impaired and delayed healing
  • infections
39
Q

What can you do as a Dental Professional (6)

A

OHI
regular check ups
antibiotics
control blood levels before surgery
mouth wash
if required - artificial saliva

40
Q

What is the Only Energy Substrate for the Brain?

A

Glucose

41
Q

What is the mass of one molcules of Glycogen?

A

10^8 Daltons

42
Q

Which 2 Hormones Promote Breakdown?

A

Glucagon and Adrenaline in the liver
Adrenaline in the muscles

43
Q

The Role of Glycogen Phosphorylase

A

activates to increases the levels of glucagon and adrenaline in the blood

stops cleaving when it gets within 4 units of a branch point

44
Q

What other Enzymes are Required when Glycogen Phosphorylase reaches a Branch Point?

A

transferase enzyme
- transfers 3 glucose units from one end to the other end of the chain

amylo-a-1,6-glucosidase
- hydroylses the single glucose unit left behind

45
Q

what is the reaction involving the breakdown of glycogen?

A

GLYCOGENOLYSIS
glycogen + pi = glucose-1-phosphate + glycogen

by glycogen phosphorylase

G1P:glucose ratio = 8:1

46
Q

How do the Hormone Signals Work?

A
  • adrenaline and glucagon receptors on the cystol
  • activated
  • activate adenylate cyclase
  • catalysed ATP into cAMP
    = amplification cascade
47
Q

Give 5 Types of Glycogen Storage Diseases FMVAP

A

Andersen Disease - 1,4-a-glucan glucosidase
- affects liver
= death in 3 years

Forbes’ Disease - amyloid-1,6-glucosidase
- affects liver, muscle, heart
= good prognosis

Pompe’s Disease - lysosomal a-glucosidase
- affects liver, muscle, heart
= death in first 6 months

McArdle Disease - phosphorylase
- affects muscle
= normal lifestyle, must avoid exercise

Von Glerke’s Disease - glucose-6-phosphatase
- affects liver, intestine, kidney
= if survive hypoglycaemia, prognosis is good, hyperuricaemia is a later complication

48
Q

Define Glycogenesis

A

glycogen synthesis

49
Q

How do you Obtain Branching Point on Glucagon?

A

transfer min 6 alpha-1,4-glucose units onto the chain by introducing a a-1,6 linkage

Use CBE branching enzyme

50
Q

What if you have a Deficiency of the Branching Enzyme?

A

leads to Anderson’s Disease
= liver failure and death in first year of life

51
Q

How Does Insulin Work?

A

insulin receptors on the cystol activate
- activate protein kinase

52
Q

Insulin in the Muscles

A
  • increases no. of membrane glucose transporters
  • activate glycogen synthesis
53
Q

Insulin in the Liver

A

doesn’t affect the number of membrane glucose transporters
- activates glycogen synthesis

54
Q

How much Glycogen can be Stored?

A

300g
- after, glucose entering liver is converted to fat and sent to adipose

55
Q

Define Gluconeogenesis

A

the synthesis of new glucose made from noncarbohydrate sources in the liver using the precursors lactate, glycerol and amino acids

56
Q

How much energy does Gluconeogenesis use?

A

4ATP
2GTP
2NADH

-16kJ/mol

Yr 2 - IBMS (21 decks)

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